Infrastructure Engineering - Research Publications

Permanent URI for this collection

Search Results

Now showing 1 - 6 of 6
  • Item
    No Preview Available
    The proposed heating and cooling system in the CH2 building and its impact on occupant productivity
    AYE, L ; FULLER, RJ (Australian Institute of Quantity Surveyors, 2005-12-31)
    Melbourne's climatic conditions demand that its buildings require both heating and cooling systems. In a multi-storey office building , however, cooling requirements will dominate. How the internal space is cooled and ventilation air is delivered will significantly impact on occupant comfort. This paper discusses the heating and cooling systems proposed for the CH2building. The paper critiques the proposed systems against previous experience, both internationally and in Australia. While the heating system employs proven technologies, less established techniques are proposed for the cooling system. Air movement in the shower towers, for example, is to be naturally induced and this has not always been successful elsewhere. Phase change material for storage of "coolth" does not appear to have been demonstrated previously in a commercial building, so the effectiveness of the proposed system is uncertain. A conventional absorption chiller backs up the untried elements of the cooling system, so that ultimately occupant comfort should not be compromised.
  • Item
    Thumbnail Image
    Simulation study of a down-draft wood gasifier used to produce thermal energy for tea drying
    Jayah, T ; Aye, L ; Fuller, RJ ; Stewart, DF (ANZSES Australia & New Zealand Solar Energy Society, 2000-11-29)
    A detailed computer model has been developed using the physical and chemical phenomena in gasification for a down-draft biomass gasifiers. The model has been used to investigate the effects of operational and design parameters on reactor performance in terms of the composition of the output gas and the hot gas efficiency. The results obtained from the simulation study are the effects of fuel moisture content, particle size, feed rate, reactor load and capacity on hot gas efficiency. The model has been validated using experimental data available in the open literature. The hot gas efficiency of a particular down-draft throated gasifier designed to generate thermal energy for tea drying is predicted to be approximately 86%.
  • Item
    Thumbnail Image
    An evaluation of a proposed ventilation system for Melbourne's CH2 building
    AYE, L ; FULLER, RJ (Australian Institute of Quantity Surveyors, 2005-12-31)
    The understanding of ventilation requirements in commercial buildings has been significantly revised in the last 10-15 years. A link between health, productivity and increased fresh air use has been established by some research and this understanding underpins the ventilation philosophy adopted for the CH2 building. The ventilation system design for CH2 that has been evaluated in this paper envisages a mechanically driven system during the day, using the displacement technique to distribute filtered air. All introduced air will be drawn from outside and no recycling of air will occur. Natural ventilation will be employed at night using the stack effect, enhanced by turbine ventilators. This paper critiques the proposed ventilation system in the light of international experience and the particular conditions of the building's location. The evidence suggests that natural ventilation sometimes may be inadequate to achieve the desired objectives. Minimization of indoor pollutants, adequate filtration and high levels of ventilation should, however, ensure satisfactory air quality during occupied hours.
  • Item
    No Preview Available
    Thermal evaluation of a greenhouse in a remote high altitude area of Nepal
    Fuller, RJ ; Aye, L ; Zahnd, A ; Thakuri, S (RERIC, 2009-06-01)
    Remote communities in the high altitude areas of Nepal suffer both chronic and acute malnutrition. This is due to a shortage of arable land and a harsh climate. For seven months of the year, the harvesting of fresh vegetables is almost impossible. Greenhouse technology, if appropriate for the location and its community, can extend the growing season considerably. Experience in the Ladakh region of India indicates that year-round cropping is possible in greenhouses in cold mountainous areas. A simple 50-m 2 greenhouse has been constructed in Simikot, the main town of Humla, northwest Nepal. This paper describes the evaluation of the thermal performance of that greenhouse. Both measurement and simulation were used in the evaluation. Measurements during the winter of 2006-7 indicate that the existing design is capable of producing adequate growing conditions for some vegetable crops, but that improvements are required if crops like tomatoes are to be grown successfully. Options to improve the thermal performance of the greenhouse have been investigated by simulation. Improvements to the building envelope such as wall insulation, double-glazing and using a thermal screen were simulated with a validated TRNSYS model. The impact of the addition of nighttime heat from internal passive solar water collectors was also predicted. The simulations indicate that the passive solar water collectors would raise the average greenhouse air temperature by 2.5°C and the overnight air temperature would increase by 4.0°C. When used in combination, overnight temperatures are predicted to by almost 7°C higher.
  • Item
    No Preview Available
    The potential of wood gasifiers for tea drying in Sri Lanka
    JAYAH, TH ; FULLER, R ; AYE, L ; STEWART, D (RERIC, 2001-12-01)
    One of the reasons for the higher production cost of tea in Sri Lanka compared to other countries is the high specific energy consumption. In Sri Lanka, 38% more energy is used to produce one kilogram of tea compared to India, largely because of the use of inefficient wood-fired air heaters. Gasifiers have been proposed as an alternative method of providing the hot air used for drying. A locally built gasifier has been tested and found to have a conversation efficiency of 80%, which is comparable to that of an imported unit. The heat loss of local gasifier was found to be between 11.5-14% of the input energy. An analysis shows that the life cycle cost of energy produced by the gasifier is US$ 3.00 per GJ, which is 8% less than the cost of energy from a conventional wood heater. Wood consumption is also reduced by 12%. Some transfer of gasifier technology to the crematoria industry in Sri Lanka has already occurred and this enhances the prospect of the successful introduction of this technology to the tea industry.
  • Item
    Thumbnail Image
    Computer simulation of a downdraft wood gasifier for tea drying
    JAYAH, TH ; AYE, L ; FULLER, RJ ; STEWART, DF (Elsevier, 2003-10-01)
    A gasifier has been fabricated in Sri Lanka for the tea industry, but there is a lack of knowledge of the effect of certain key operating parameters and design features on its performance. Experimental testing of the design under various conditions has produced data that has then been used to calibrate a computer program, developed to investigate the impact of those parameters and features on conversion efficiency. The program consists of two sub-models of the pyrolysis and gasification zones, respectively. The pyrolysis sub-model has been used to determine the maximum temperature and the composition of the gas entering the gasification zone. The gasification zone sub-model has been calibrated using data gathered from the experiments. It was found that a wood chip size of 3–5 cm with a moisture content below 15% (d.b.) should be used in this gasifier. Feed material with a fixed carbon content of higher than 30% and heat losses of more than 15% should be avoided. For the above parameters, the gasification zone should be 33 cm long to achieve an acceptable conversion efficiency.